Add Llama Flax Implementation (huggingface#24587)

* Copies `modeling_flax_gpt_neo.py` to start

* MLP Block. WIP Attention and Block

* Adds Flax implementation of `LlamaMLP`
Validated with in-file test.
Some slight numeric differences, but assuming it isn't an issue

* Adds `FlaxLlamaRMSNorm` layer
`flax.linen` includes `RMSNorm` layer but not necessarily in all
versions. Hence, we add in-file.

* Adds FlaxLlamaAttention
Copied from GPT-J as it has efficient caching implementation as well as
rotary embeddings.
Notice numerically different, but not by a huge amount. Needs
investigating

* Adds `FlaxLlamaDecoderLayer`
numerically inaccurate, debugging..

* debugging rotary mismatch
gptj uses interleaved whilst llama uses contiguous
i think they match now but still final result is wrong.
maybe drop back to just debugging attention layer?

* fixes bug with decoder layer
still somewhat numerically inaccurate, but close enough for now

* adds markers for what to implement next
the structure here diverges a lot from the PT version.
not a big fan of it, but just get something working for now

* implements `FlaxLlamaBlockCollection`]
tolerance must be higher than expected, kinda disconcerting

* Adds `FlaxLlamaModule`
equivalent PyTorch model is `LlamaModel`
yay! a language model🤗

* adds `FlaxLlamaForCausalLMModule`
equivalent to `LlamaForCausalLM`
still missing returning dict or tuple, will add later

* start porting pretrained wrappers
realised it probably needs return dict as a prereq

* cleanup, quality, style

* readds `return_dict` and model output named tuples

* (tentatively) pretrained wrappers work 🔥

* fixes numerical mismatch in `FlaxLlamaRMSNorm`
seems `jax.lax.rsqrt` does not match `torch.sqrt`.
manually computing `1 / jax.numpy.sqrt` results in matching values.

* [WIP] debugging numerics

* numerical match
I think issue was accidental change of backend. forcing CPU fixes test.
We expect some mismatch on GPU.

* adds in model and integration tests for Flax Llama
summary of failing:
- mul invalid combination of dimensions
- one numerical mismatch
- bf16 conversion (maybe my local backend issue)
- params are not FrozenDict

* adds missing TYPE_CHECKING import and `make fixup`

* adds back missing docstrings
needs review on quality of docstrings, not sure what is required.
Furthermore, need to check if `CHECKPOINT_FOR_DOC` is valid. See TODO

* commenting out equivalence test as can just use common

* debugging

* Fixes bug where mask and pos_ids were swapped in pretrained models
This results in all tests passing now 🔥

* cleanup of modeling file

* cleanup of test file

* Resolving simpler review comments

* addresses more minor review comments

* fixing introduced pytest errors from review

* wip additional slow tests

* wip tests
need to grab a GPU machine to get real logits for comparison
otherwise, slow tests should be okay

* `make quality`, `make style`

* adds slow integration tests
- checking logits
- checking hidden states
- checking generation outputs

* `make fix-copies`

* fix mangled function following `make fix-copies`

* adds missing type checking imports

* fixes missing parameter checkpoint warning

* more finegrained 'Copied from' tags
avoids issue of overwriting `LLAMA_INPUTS_DOCSTRING`

* swaps import guards
??? how did these get swapped initially?

* removing `inv_freq` again as pytorch version has now removed

* attempting to get CI to pass

* adds doc entries for llama flax models

* fixes typo in __init__.py imports

* adds back special equivalence tests
these come from the gpt neo flax tests. there is special behaviour for these models that needs to override the common version

* overrides tests with dummy to see if CI passes
need to fill in these tests later

* adds my contribution to docs

* `make style; make quality`

* replaces random masking with fixed to work with flax version

* `make quality; make style`

* Update src/transformers/models/llama/modeling_flax_llama.py

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* Update src/transformers/models/llama/modeling_flax_llama.py

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* Update src/transformers/models/llama/modeling_flax_llama.py

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* Update src/transformers/models/llama/modeling_flax_llama.py

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* Update src/transformers/models/llama/modeling_flax_llama.py

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* Update src/transformers/models/llama/modeling_flax_llama.py

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* updates `x`->`tensor` in `rotate_half`

* addresses smaller review comments

* Update docs/source/en/model_doc/llama.md

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* adds integration test class

* adds `dtype` to rotary embedding to cast outputs

* adds type to flax llama rotary layer

* `make style`

* `make fix-copies`

* Apply suggestions from code review

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* applies suggestions from review

* Update modeling_flax_llama.py

* `make fix-copies`

* Update tests/models/llama/test_modeling_llama.py

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* Update src/transformers/models/llama/modeling_flax_llama.py

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* fixes shape mismatch in FlaxLlamaMLP

* applies some suggestions from reviews

* casts attn output logits to f32 regardless of dtype

* adds attn bias using `LlamaConfig.attention_bias`

* adds Copied From comments to Flax Llama test

* mistral and persimmon test change -copy from llama

* updates docs index

* removes Copied from in tests

it was preventing `make fix-copies` from succeeding

* quality and style

* ignores FlaxLlama input docstring

* adds revision to `_CHECKPOINT_FOR_DOC`

* repo consistency and quality

* removes unused import

* removes copied from from Phi test

now diverges from llama tests following FlaxLlama changes

* adds `_REAL_CHECKPOINT_FOR_DOC`

* removes refs from pr tests

* reformat to make ruff happy

---------

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

src/transformers/models/llama/__init__.py

@@ -107,6 +107,14 @@
  else:
  from .modeling_flax_llama import FlaxLlamaForCausalLM, FlaxLlamaModel, FlaxLlamaPreTrainedModel
 
+ try:
+ if not is_flax_available():
+ raise OptionalDependencyNotAvailable()
+ except OptionalDependencyNotAvailable:
+ pass
+ else:
+ from .modeling_flax_llama import FlaxLlamaForCausalLM, FlaxLlamaModel, FlaxLlamaPreTrainedModel
+
 
 else:
  import sys